Heat the oil in a large non-stick pan over a medium heat and fry the sweet potato, celery, garlic and mushrooms for 10 mins, stirring occasionally until softened. Meanwhile, heat the oven to 190C/170C fan/gas 5 and line a large loaf tin with non-stick baking parchment.

Weigh 75g of the cooked veg into a bowl and set aside. Tip the rest into a bowl with the oats, lentils, almonds, tomato purée and basil, and blitz with a hand blender to make a firm purée. (Or, do this in a food processor.) Pack the mixture into the tin and press the reserved veg into the top. Bake for 40 mins, or until firm enough to slice. Leave to cool in the tin for 5-10 mins before removing to a board or plate.

Meanwhile, for the sauce, blitz the tomatoes, balsamic vinegar and garlic until smooth, then pour into a pan. Cook over a low heat for a few minutes until the garlic has softened, then add 1-2 tbsp water until the mixture has a spoonable consistency. Stir in the basil. Boil or steam half the broccoli, if using. Serve half the sauce with half the sliced loaf and the broccoli or salad. Leave the rest to cool completely and chill for another day. Will keep chilled for up to four days. Reheat the loaf and sauce on serving plates in the microwave until piping hot, and cook the remaining broccoli to serve.